Get an iPad 2 if budget allows, because the latest firmware is already hampering performance on iPad 1 (issues with memory handling). The iPad 2 has twice as much memory (that's different from GBs) as iPad 1, and faster innards overall.
iPad 2 also is likely to get firmware upgrades longer than iPad 1 at this point, and resale value will be higher for iPad 2, if that's a concern. We're only a few months from iPad 3 if Apple sticks to usual production patterns, which would put iPad 1 two generations behind.
For reference, I have iPad 1 and 2. My iPad 1 has served me well, but I sure wouldn't buy one at this point.